The present disclosure relates generally to chip manufacturing, and more particularly to methods and systems of electromigration wearout detection circuits.
With continued density scaling of integrated circuits, heat dissipation of local circuits on chips becomes growingly higher than ever, and normal operation temperature of certain areas of the integrated circuits are running hotter than the ambient temperature, especially for certain high-activity and high-load circuits such as clock buffers, and input/output (I/O) drivers, etc. Conventional on chip temperature measurement (diode sensors) no longer effective for monitoring certain circuit reliability degradation in these critical hot circuits area of the integrated circuit. Specifically, electromigration in metal wires occurs when current is flowing and the wires are hot. Electromigration leads to an increase in resistance and, eventually, to breaks in the wires. It is desirable to monitor actual product circuits themselves, and take certain mitigation actions when the circuit reliability degradation reaches a predetermined safety threshold. Monitoring of electromigration is done by periodically determining if the resistance of current-carrying wires has reached the safety threshold.
Therefore, heretofore unaddressed needs still exist in the art to address the aforementioned deficiencies and inadequacies.